Solid Brass Belt Loop Keeper Solid Brass Belt Loop Keeper, ideal for holding down the end of your strap once it's gone through the buckle. They're ideal for use on belts, dog collars and bag straps. Please note these are traditionally sand cast brass keepers that will display some of the character associated with solid brass. Although we strive to select the best quality available they may not be perfectly smooth. Please see photos. These cast brass belt keepers are available in the following sizes: 25 mm - The internal width is designed to fit the width of a 25 mm strap. It has an external width of 31 mm and internal depth of 11 mm at the centre (9 mm at the side). 30 mm - The internal width is designed to fit the width of a 25 mm strap. 32 mm (1.25 inch) - The internal width is designed to fit the width of a 32 mm strap. It has an external width of 38 mm and internal depth of 11 mm at the centre (9 mm at the side). 40 mm (1.5 inch) - The internal width is designed to fit the width of a 40 mm strap. It has an external width of 46 mm and internal depth of 11 mm at the centre (9 mm at the side). Recommended for use with leather belt and strap cutter tool.